Coil winding machine



July 1962 YOSHINOBU YOJIMA 3,047,246

con WINDING MACHINE Filed Sept. 24, 1959 This invention relates to acoil winder and more particularly to a machine for forming coils orwindings directly on transformer cores of wound type.

For many years there has been practiced a machine for winding coils onseamless transformer cores having areas of core windows relativelylarger than cross-sectional areas of coils as wound on the same. Suchcores may be of toroidal type and mainly used to manufacture repeatercoils or autotransformers having variable output voltages and knownunder trademark Variac.

Also, to form windings on transformer cores of Wound type increasinglyused in recent years, there have been proposed various winding systemssuch as a cut core system, a round coil system, a round core system anda Spina Kore system. The cut core system includes many steps of cuttinga core and needs to use the core having cut surfaces thereof in intimatecontact with each other. This results in the use of expensive machinetools. Further it has disadvantage that any void between the adjacentcut surfaces of the core will increase electrical loss. In the roundcoil type, a bobbin rotatably mounted on a leg of a transformer corewill be rotated about the leg for forming a winding. Therefore, the legshould be of circular cross section. This leads to increase in the totallength of magnetic path of the core and hence to a large sizedtransformer. This is true in the case of the round core system. TheSpina Kore system has disadvantages such as strain of silicon steelstrips used, non-uniformity and deterioration in characteristics of thefinished products. In brief any of such winding systems isdisadvantageous in that the finished products will be not onlydeteriorated in electrical characteristics but also will be expensive.

One object of the invention is to provide a simple, inexpensive coilwinder whereby a coil can be wound directly on a leg of a wound typetransformer core with the latter not subjected to any machiningoperation.

Another object of the invention is to provide a coil winder of the typedescribed in the preceding paragraph, wherein a relatively fine wire canbe used.

The principle of the invention is that, at each time a winding isdesired to be formed on a transformer of Wound type, a wire winding unitis caused to be formed about the core leg on which the winding will beformed, with the unit extending through the window or windows of thecore and with the unit arranged to be rotated about the leg while movedalong the same by means of a driving mechanism known per se.

The invention will be more readily apparent from the followingdescription in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of essential parts of a coil winderembodying the invention and illustrating the manner in which a windingis'formed on a transformer core of wound type;

FIGS. 2 and 3 show respectively a plan and a side elevational view ofone of elements forming a wire guiding capstan used in the winder ofFIG. 1;

FIGS. 4 and 5 show respectively a plan and a side elevational View ofthe other element forming the capstan;

FIG. 6 shows in radial section one portion of the capstan, andillustrates the manner in which the capstan including a length of wirewound on its periphery en gages one of grooved rollers for supportingthe capstan;

Patented July 31, 1962 FIG. 7 is a side view of a tensioning device.

While the invention is applicable to make a winding or windings on atransformer core of each of shell type and core type, it will bedescribed in conjunction with a shell type core.

Referring to FIG. 1 there is shown a transformer core 10 of shell typecomprising a pair of Wound type core members 12 substantially identicalwith each other, with the longer leg of one member juxtaposed in contactwith the longer leg of the other core member to form the middle leg 14of the core. As shown in FIG. 1, the core member 12 is of rectangularcross-section and of rectangular configuration. It is assumed that alength of a relatively fine wire is to be wound on a primary windingalready formed on the core leg 14, to form a secondary winding or a highvoltage winding with a layer of any suitable insulating materialinserted therebetween. The formation of the primary winding will beexplained in detail hereinafter.

FIG. 1 also illustrates essential parts of a winding machine embodyingthe present invention. The core is rigidly mounted in position in themachine by any suitable means with one end thereof substantiallycontacting a supporting plate 16 secured to a machine frame (not shown).The supporting plate comprises a number of short rods 13 secured theretoand having their free end portions on which grooved supporting rollers2% are mounted for rotation respectively. The rollers can rotatablysupport a wire guiding capstan of annular shape generally designated by22.

As shown in FIGS. 2 and 3, the wire guiding capstan 22 comprisespreferably a pair of sernicircularly arcuate members 24 made of anysuitable material such as soft steel and capable of being interconnectedat their stepped ends as by screws 26 to form a complete annularstructure. This construction of the capstan makes it possible to readilyassemble and disassemble to same on the rollers 20 as describedhereinafter. The member 24 has its outer stepped peripheral portion 28of the largest diameter which is toothed for the purpose explainedhereinafter (FIGS. 2 and 3). -The capstan has a guide ring 30 disposedin the peripheral trough. As shown in FIGS. 4 and 5, the guide ring 3%comprises a pair of semicircular pieces each having an outwardly radialand circumferential extensions at its end and an inner diametersubstantially equal to the least diameter of the capstan 22. Thesemicircular piece may be of any suitable material such as soft steel.One of these semicircular pieces is provided with a radial projectionincluding an aperture, or eye 32 therein for guiding a wire to be wound.The two-piece ring 30 can readily be fitted into the peripheral troughof the capstan 22 by placing the respective semicircular pieces on thetrough, abutting against each other and by interconnecting theirextensions as by screws. The dimension of the guide ring 30 is selectedsuch that it can slide on the periphery of the capstan freely andsmoothly.

The wire guiding capstan 22 can readily be supported on the groovedrollers 20 around the middle leg 14 of the core 10 by inserting eachring member 24 thereof within one of core windows formed of the middleleg,

the outer legs and the yokes of the core, resting on the rollers 20 withits internal periphery fitted into the grooves of the latter, abuttingthe stepped ends against each other and then interconnecting those endsby the screws 26 to form one piece. Thereafter the guide ring 30 can bemounted to the united capstan 22' as described above. The thickness ofthe capstan and the width of the groove on the roller are selected thatthe capstan as supported to the rollers is prevented from movingrelative to the rollers lengthwise of the same.

The wire guiding capstan 22 as supported by the 3 grooved rollers 20 isarranged to be meshed at its peripheral toothed portion 28 with a gear34 secured to a driving shaft 36 connected to a drive (not shown). Thusthe drive can rotate the capstan about the core leg 14.

The capstan 22 can readily be removed from the rollers 20 by means ofthe operation reverse to that described just above.

A wire winding unit generally designated by 40 is provided for windingon the core leg 14 a length of wire as fed from a supply roll (notshown) through the wire guiding capstan 22. The feeding of the wire willbe described hereinafter. The winding unit 40 consists of an endlessbelt 42 adapted to be spanned between and travel on four grooved pulleys44 disposed substantially in a rectangular arrangement. The endless belt42 is preferably formed of leather or cotton fabric and includes a smallguide piece 46 attached on its outer surface as by rivets and arrangedin such a way that the piece has its end portion projecting toward thewire guiding capstan 22 from that edge of the belt facing the same whenthe belt and the capstan are in their operating positions. Saidprojecting end portion of said guide piece 46 is provided with an eye48, through which the wire is passed and wound on the core leg 14. Thebelt as unused is in the form of an elongated strip having end portions,and this can readily be formed into one endless belt by passing the samearound the four pulleys 44 and joining the end portions. By disengagingthis joint, the belt can readily be removed from the rollers.

The pulleys 44 are rotatably carried through rods 52 by a U-shapedbracket 54, each arm carrying two rods 52. The upper arm of the bracket54 has an extension 56 capable of being secured to the same at anydesired angle with respect to that arm on the plane of the bracket bymeans of a bolt 58. The extension 56 is provided at its free end withthe rod 52 secured thereto, on which the pulleys 44 is rotatablymounted. Therefore, after the endless belt 42 has engaged the pulleys44, its tension can readily be adjusted by changing the angle of theextension 56 with respect to the upper arm of the bracket.

The endless belt 42 is adapted to run around the core leg 14 by therotation of the pulleys 44 and simultaneously to be moved sidewisetogether with the rollers 42 and bracket 54. Various mechanism foreffecting simultaneous rotational and sidewise movements of the endlessbelt are well known in the art. One form of such mechanisms is shown inFIG. 1, wherein all the pulleys 44, excepting the tensioning guidepulley on the extension 56, are driven by a driving shaft 60 throughsprocket wheels 61 to 66 and sprocket chains 67 to 69, whereby the beltruns around the core leg 14. To effect the sidewise translationalmovement of the belt along the core leg 14, the U-shaped bracket 54 isprovided on its base portion with a short, internally threaded sleeve 70secured thereto and engaging with a feed screw 72 extendingtherethrough.

The feed screw 72 is rotatably mounted to the machine frame (not shown)and can be selectively coupled to the driving shaft 60 in such a mannerthat the endless belt 42 will be moved along the core leg 14 by adistance substantially equal to the diameter of the wire to be wound onthe leg during one complete rotation of the same. A bar 74 parallel tothe feed screw 72 extends through the base portion of the bracket 54 andserves to guide the winding unit 40 along the core leg 14 with thebracket prevented from turning on the feed screw.

It is noted that the driving shaft 60 is coupled to the driving shaft 36through a transmission device (not shown) in a predeterminedrelationship as described hereinafter.

It will be understood that the four pulleys 44 be positionedsubstantially in rectangular arrangement such that two horizontalportions of the belts as well as the two vertical portions thereof asviewed in FIG. 1 are spaced away from each other by a distance more thanthe maximum diameter of the finished winding formed on the core leg 1-4with the vertical portions being within the core windows. It will beseen that the spacing between the pulleys can be selected such that thefinished winding will occupy a substantial portion of the window area.This is desirable for power transformers.

The operation of the machine described above is as follows:

Assuming that, as described previously the wire guiding capstan 22 isassembled on the grooved rollers in the close proximity to the end ofthe middle leg 14 Within the core windows of the core 10 mounted to themachine, the winding unit 40 assembled as explained previously is alsopositioned in the close proximity to the opposite end of the core leg 14within the core windows. With the capstan 22 and the unit 40 being insuch positions, no winding can be formed on that portion of the lengthof the core leg 14 substantially corresponding to a distance between theend face of the core window and each of the sides of the capstan and theunit remote apart from the respective end face of the core window, sothat the dimensions of such components measured along the core leg arepreferably as small as possible with the spacing between that end faceand the side of the component facing the same also maintained as smallas possible.

A relatively fine wire 84 fed from a supply roll (not shown) is passedtwice or thrice around the united arcuate members 24 of the capstan 22,threaded through the aperture 32 of the guide ring (see FIG. 6), andthence passed through a tensioning device 78 which will be describedlater, to the wire guiding eye 48 formed on the endless belt 42. Thewire as having passed through the eye 48 has a few turns manually woundon the core leg 14 at a predetermined position adjacent to its oppositeend mentioned previously with the end portion of the wire drawn outexternally of the core as shown in FIG. 1. Then the winding operationcan be started.

In FIG. 7 the tensioning device 78 is shown as comprising three spacedtensioning rollers 80 rotatably mounted to a support plate 82 with theircenters lying substantially in a straight line. The support plate 82 maybe suitably secured at one end to the guide piece 46 on the endless belt42 and the wire 84 extend successively around the lower side of thefirst roller, the upper side of the second and the lower side of thethird roller until threads the guide hole 48. This construction of thetensioning device can impart an appropriate tension to the Wire beingwound thereby to tightly wind the same on the core leg. The tensioningdevice also serves to draw continuously the wire being wound nearertoward the guiding hole 48.

The tensioning device 78 may be replaced by a helical spring having oneend secured to the guide piece 46 and the other end formed in the formof hook adapted to engage the wire 84.

With the capstan 22, the winding unit 40 and the first portion of thewire 84 disposed as shown in FIG. 1, and with the rotation of the feedscrew 72 adjusted to effect the translational movement of the windingunit toward the capstan 22, the driving shaft 60 can be manually orelectrically driven to start the winding operation. Assuming that theshaft 60 is rotated counterclockwise as viewed in FIG. 1, the guiderollers 44 also are rotated to move the endless belt 42 on these rollersabout the core leg 14 counterclockwise, whereby the wire is wound on thelatter. Simultaneously, the feed screw 72 is rotated to move the windingunit 40 toward the guiding capstan 22. As pointed out previously, theendless belt 42 and hence the wire guiding eye 48 is adjusted to bemoved along the core leg by a length substantially equal to the diameterof the wire 84 during one complete revolution of the same. Therefore,the resulting turns of the wire are very close to each other.

As the 'wire is Wound on the core leg, the succeeding wire iscontinuously fed from the supply roll through the wire guiding capstan22. that the guiding capstan 22 in its operating position should includealways a substantially constant length of the wire wound on theperiphery thereof. To this end the driving shaft 36 for the capstan 22is coupled through coupling Qmeans (not shown) to the driving shaft 6%for the winding unit 40 in such a manner that the former shaft willrotate the capstan 2.2 in the direction opposite to the direction ofrotation of the endless belt 42 at a rate which the linear speed of thewire as wound on the core leg will be approximately equal to that asleaving the capstan 22 through the wire guiding eye 48 and hence aswound on the capstan. Also, as described previously, the guide ring 80is arranged to be freely rotated relative to the united ring members 24.This permits the guide ring 3% to be rotated at a rate substantiallyequal to the speed of rotation of the belt 42 in the direction thereofby virtue of the tension of the travelling wire 84. Therefore, the guidering 30 is rotated opposite to the united arcuate members 24 thereby tounwind the wire from the capstan 22 at the linear speed mentioned above.This prevents any variation in the tension of the travelling wire andaccordingly prevents the same from being broken down due to suchvariation.

When the leading turn of the Wire reaches a predetermined position onthe core leg adjacent to its end at which the Wire guiding capstan 22 isdisposed, the rotation of the feed screw 72 is reversed in a manner wellknown in the art. Then, the winding unit 46 is moved in the reversedirection along the core leg 14 while rotated about the same to form alayer of turns superposed on the first layer of turns. A layer of anysuitable insulatingmaterial may be inserted between the first and secondlayers of turns. In this manner a winding is'formed in any suitablenumber of turn-layers. 'The winding is completed by fixing the end turnin any conventional manner.

While the invention has been described in conjunction with certainspecific embodiments thereof, it is to be understood that variouschanges and modifications may be made Without departing from the spiritand. scope of the invention.

What I claim is:

1. A winding machine for forming a wire winding on a leg, havingoppositely disposed ends, of a wound type transformer core, said machinecomprising: roller means mounted around the perimeter of one end of saidlegs oppositely disposed ends and spaced radially therefrom; a wireguiding capstan for initially engaging said wire to be wound anddefining an annulus supported on said rollers for rotation around saidone end of said leg, said capstan having a peripheral wire windingsurface for engaging several turns of wire to be Wound, and a peripheraltrough; a guide ring slidably mounted for free rotation in the same andopposite directions of capstan rotation in said peripheral trough, saidguide ring having a wire-guiding aperture through which the wire tobe'wound is passed from said peripheral wire winding surface; pulleymeans mounted around the perimeter of the other end of said legsoppositely disposed ends and spaced radially there from; an endless beltmounted on said pulleys and driven in this connection it is noted aroundsaid leg, said belt having a wire guiding perforation through which thewire to be wound is passed from said wire guiding aperture 02": saidguide ring, for winding by said endless belt on said leg; means fordriving said belt on said pulleys. around said leg and moving said beltand supporting pulleys from said other end toward said one end of saidleg at least the thickness of said wire to be wound for every revolutionof the wire guiding perforation of said endless belt; and means forrotating said wire guiding capstan opposite to the rotation of saidendless belt for winding on said peripheral wire winding surface saidwire to be wound, whereby the wire wound on said capstan by the rotationthereof is unwound therefrom by the opposite rotation of said slidablymounted guide ring driven by said endless belt and the tension in thewire therebetween and wound on said leg.

2. A Winding machine as claimed in claim 1, wherein 'a device fortensioning wire is coupled to said endless belt adjacent to said Wireguiding perforation of said belt and comprises three rollers mountedrelative to each other to change the direction of linear travel of saidwire travelling between said rollers.

3. A winding machine according to claim 1 wherein said wire guidingcapstan comprises two semicircular members, and means connecting theends thereof to form an annulus whereby said capstan can be readilyassembled and disassembled around a closed end of a leg core.

4. A winding machine according to claim l'wherein said means forrotating said capstan rotates it at a rate at which the linear speed ofthe Wire entering and leaving the capstan will be approximately equal tothe linear speed of the wire wound on the core leg by the oppositerotation of said endless belt, whereby small variations in said relativelinear speeds merely increases and decreases the length of wire in theturns around said peripheral wire winding surface of said capstanthereby avoiding breaking and loosening the wire.

5. A winding machine for forming a winding on a leg of a wound typetransformer core having lateral dimensions, said machine including awinding unit, wherein said winding unit comprises an endless belt havinga guiding eye for receiving a wire to be wound, said endless belt beingdisposed on rollers around the core leg so as to conform to each saidlateral dimension, means for driving said endless belt around the coreleg, means for gradually shifting said belt sidewise, a wire guidingcapstan surrounding one end of the core leg and adapted to be rotated atthe same speed and in the opposite direction as said endless belt, and aguide ring having a wire guiding eye and loosely mounted on said capstanand adapted to freely rotate in the same direction as the endless beltby virtue of the tension of the wire, whereby wire Wound on said capstanby the rotation thereof and threaded through said guide ring eye to saidbelt eye is unwound from said capstan and wound on said core by therotation of said belt.

References Cited in the file of this patent UNITED STATES PATENTS

